Abdominal wall vertical muscles

Rectus abdominisPyramidalis

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Rectus abdominis

Long paired muscles split at midline by linea alba and horizontally by tendinous intersections giving the 6 pack appearance.

Attachments: Originates from the crest of the pubis, before inserting into the xiphoid process of the sternum and the costal cartilage of ribs 5-7.Functions: As well as assisting the flat muscles in compressing the abdominal viscera, the rectus abdominis also stabilises the pelvis during walking, and depresses the ribs.Innervation: Thoracoabdominal nerves (T7-T11).

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Pyramidalis

This is a small triangular muscle, found superficially to the rectus abdominis

Attachments: Originates from the pubic crest and pubic symphysis before inserting into the linea alba.Functions: It acts to tense the linea alba.Innervation: Subcostal nerve (T12).

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Horizontal and vertical planes making up the nine regions of abdomen surface anatomy

Transpyloric planeIntertubercular planeMid clavicular lines

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What lies on the transpyloric plane

Origin of SMA, portal veinSpleenNeck of pancreasPylorus of stomach Fundus of gallbladderHilum of kidneysL1, just before end of spinal cordduodenojejunal flexure

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5 major posterior abdominal muscles

Psoas majorPsoas minorIliacusQuadratus LumborumDiaphragm

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Quadratus lumborum

Located laterally in the posterior abdominal wall

Attachments: It originates from the iliac crest and iliolumbar ligament, travels superomedially, inserting onto the transverse processes of L1 – L4 and the inferior border of the 12th rib.Actions: Extension and lateral flexion of the vertebral column. It also fixes the 12th rib during inspiration, so that the contraction of diaphragm is not wasted.Innervation: Anterior rami of T12- L4 nerves.

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Psoas major

Near the midline of the abdominal wall lateral to the lumbar vertebrae

Attachment: Originates from the transverse processes and vertebral bodies of T12 – L5. It then moves inferiorly and laterally, running deep to the inguinal ligament, and attaching to the lesser trochanter of the femurActions: Flexion of the thigh at the hip and lateral flexion of the vertebral column.Innervation: Anterior rami of L1 – L3 nerves.

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Psoas minor

Only in 60% of the population. Anterior to psoas major

Attachments: Originates from the vertebral bodies of T12 and L1 and attaches to a ridge on the superior ramus of the pubic bone, known as the pectineal line.Actions: Flexion of the vertebral column.Innervation: Anterior rami of the L1 spinal nerve.

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Iliacus

Fan shaped muscle. It combines with the psoas major to form the iliopsoas – the major flexor of the thigh.

Attachments: Originates from surface of the iliac fossa and anterior inferior iliac spine. Its fibres combine with the tendon of the psoas major, inserting into the lesser trochanter of the femur.Actions: Flexion of the thigh at the hip joint.Innervation: Femoral nerve (L2 – L4)

Blood supply to gallbladder

Blood supply to kidneys

Renal arteriesRenal veins drain into IVC

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Blood supply to stomach

Right gastric – branch of the hepatic artery proper.Left gastric – arises directly from the coeliac trunk.Right gastro-omental – terminal branch of the gastroduodenal artery, which arises from the common hepatic artery.Left gastro-omental – branch of the splenic artery, which arises from the coeliac trunk.

lesser curvature: right and left gastric arteriesGreater curvature: right and left gastro-omental arteries